Smithsonian/USGS Weekly Volcanic Activity Report 28 December 2011 - 3 January 2012
From: "Faulk, Elisabeth" <FaulkE@xxxxxx>
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Smithsonian/USGS Weekly Volcanic Activity Report
28 December 2011-3 January 2012
Elisabeth Faulk - Weekly Report Editor
faulke@xxxxxx
URL: http://www.volcano.si.edu/reports/usgs/
New Activity/Unrest: | Callaqui, Central Chile | Cleveland, Chuginadak Island | Galeras, Colombia | Gamalama, Halmahera | Lewotolo, Lomblen Island (Indonesia) | Lokon-Empung, Sulawesi | Poás, Costa Rica | Sorikmarapi, Sumatra (Indonesia) | Tungurahua, Ecuador
Ongoing Activity: | Fuego, Guatemala | Hierro, Canary Islands (Spain) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Popocatépetl, México | Puyehue-Cordón Caulle, Central Chile | Sakura-jima, Kyushu | Shiveluch, Central Kamchatka (Russia)
This page is updated on Wednesdays. Please see the GVP Home Page for news of the latest significant activity.
The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.
Note: Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source.
New Activity/Unrest
CALLAQUI Central Chile 37.92°S, 71.45°W; summit elev. 3164 m
Based on a pilot observation, the Buenos Aires VAAC reported that the top of an ash plume from Callaqui was at 3 km (10,000 ft) a.s.l. on 2 January. Ash was not detected in satellite imagery under clear skies.
Geologic Summary. The late-Pleistocene to Holocene Callaqui stratovolcano has a profile of an overturned canoe due to its construction along an 11-km-long, SW-NE fissure above a 1.2-0.3 million year old Pleistocene edifice. The ice-capped, 3164-m-high basaltic-andesite Callaqui volcano contains well-preserved volcanic cones and lava flows, which have traveled up to 14 km. Small craters 100-500 m in diameter are primarily found along a fissure extending down the SW flank. Intense solfataric activity occurs at the southern part of the summit; in 1966 and 1978, red glow was observed in fumarolic areas. Periods of intense fumarolic activity have dominated at Callaqui, and few historical eruptions are known. An explosive eruption was reported in 1751, there were uncertain accounts of eruptions in 1864 and 1937, and a small phreatic ash emission was noted in 1980.
Source: Source: Buenos Aires Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html
CLEVELAND Chuginadak Island 52.825°N, 169.944°W; summit elev. 1730 m
AVO reported that an ash cloud from Cleveland rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted 80 km ESE on 29 December. AVO raised the Volcano Alert Level to Watch and the Aviation Color Code to Orange. During 30 December-3 January there were no new signs of explosive activity; the Volcano Alert Level was lowered to Advisory and the Aviation Color Code to Yellow on 30 December. No current seismic information was available because Cleveland does not have a real-time seismic network.
Geologic Summary. Symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited dumbbell-shaped Chuginadak Island in the east-central Aleutians. The 1,730-m-high stratovolcano is the highest of the Islands of Four Mountains group and is one of the most active in the Aleutians. Numerous large lava flows descend its flanks. It is possible that some 18th to 19th century eruptions attributed to Carlisle (a volcano located across the Carlisle Pass Strait to the NW) should be ascribed to Cleveland. In 1944 Cleveland produced the only known fatality from an Aleutian eruption. Recent eruptions from Mt. Cleveland have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks.
Source: Alaska Volcano Observatory (AVO) http://www.avo.alaska.edu/
GALERAS Colombia 1.22°N, 77.37°W; summit elev. 4276 m
INGEOMINAS reported that activity continued at Galeras during 28 December- 3 January, with steam rising from the main crater and two craters to the N and SW (Paisita and Chavas, respectively). A web camera showed gas emissions on 28, 30, and 31 December and on 1 January. The Alert Level remains at III (Yellow; "changes in the behavior of volcanic activity").
Geologic Summary. Galeras, a stratovolcano with a large breached caldera located immediately W of the city of Pasto, is one of Colombia's most frequently active volcanoes. The dominantly andesitic Galeras volcanic complex has been active for more than 1 million years, and two major caldera collapse eruptions took place during the late Pleistocene. Longterm extensive hydrothermal alteration has affected the volcano. This has contributed to large-scale edifice collapse that has occurred on at least three occasions, producing debris avalanches that swept to the W and left a large horseshoe-shaped caldera inside which the modern cone has been constructed. Major explosive eruptions since the mid Holocene have produced widespread tephra deposits and pyroclastic flows that swept all but the southern flanks. A central cone slightly lower than the caldera rim has been the site of numerous small-to-moderate historical eruptions since the time of the Spanish conquistadors.
Source: Instituto Colombiano de Geología y Minería (INGEOMINAS) http://www.ingeominas.gov.co/Pasto.aspx
GAMALAMA Halmahera 0.80°N, 127.33°E; summit elev. 1715 m
According to news articles, at least three people were killed and 1,000-2,600 more from several villages were displaced by lahars from Gamalama during on 27-28 December. The lahars destroyed many homes in the Tubo and Tofure villages and along the Togorara and Marikurubu rivers. The Alert Level remains at 3 (on a scale from 1-4).
Geologic Summary. Gamalama (Peak of Ternate) is a near-conical stratovolcano that comprises the entire island of Ternate off the western coast of Halmahera and is one of Indonesia's most active volcanoes. The island of Ternate was a major regional center in the Portuguese and Dutch spice trade for several centuries, which contributed to the thorough documentation of Gamalama's historical activity. Three cones, progressively younger to the N, form the summit of Gamalama, which reaches 1,715 m. Several maars and vents define a rift zone, parallel to the Halmahera island arc, that cuts the volcano. Eruptions, recorded frequently since the 16th century, typically originated from the summit craters, although flank eruptions have occurred in 1763, 1770, 1775, and 1962-63.
Sources: BBC News http://www.bbc.co.uk/news/world-asia-16351244, The Jakarta Post http://www.thejakartapost.com/news/2011/12/28/cold-lava-flood-hits-gamalama-3-die.html
LEWOTOLO Lomblen Island (Indonesia) 8.272°S, 123.505°E; summit elev. 1423 m
CVGHM reported that white plumes rose 50-250 m above the summit of Lewotolo during the month of December. Seismicity increased on 31 December and intensified on 2 January, the same day incandescence was observed. Based on visual and seismic observations, CVGHM raised the Alert Level from 1 to 2 (on a scale of 1-4) on 2 January, then later that day raised the Alert Level to 3.
Geologic Summary. Anchoring the eastern end of an elongated peninsula that is connected to Lomblen Island by a narrow isthmus and extends northward into the Flores Sea, Lewotolo rises to 1,423 m. Lewotolo is a symmetrical stratovolcano as viewed from the N and E. A small cone with a 130-m-wide crater constructed at the SE side of a larger crater forms the volcano's high point. Many lava flows have reached the coastline. Historical eruptions, recorded since 1660, have consisted of explosive activity from the summit crater.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/
LOKON-EMPUNG Sulawesi 1.358°N, 124.792°E; summit elev. 1580 m
CVGHM reported that on 27 December seismic activity at Lokon-Empung suggested that an eruption had occurred, but fog prevented visual observations of the crater area. CVGHM noted on 28 December that the Alert Level remained at 3 (on a scale of 1-4), and reminded residents and tourists to not approach within a 2.5 km radius of the crater. Based on information from CVGHM, the Darwin VAAC reported that on 29 December an ash plume rose to an altitude of 3.7 km (12,000 ft) a.s.l.
Geologic Summary. The twin volcanoes Lokon and Empung, rising about 800 m above the plain of Tondano, are among the most active volcanoes of Sulawesi. Lokon, the higher of the two peaks (whose summits are only 2.2 km apart) has a flat, craterless top. The morphologically younger Empung volcano has a 400-m-wide, 150-m-deep crater that erupted last in the 18th century, but all subsequent eruptions have originated from Tompaluan, a 150 x 250 m wide double crater situated in the saddle between the two peaks. Historical eruptions have primarily produced small-to-moderate ash plumes that have occasionally damaged croplands and houses, but lava-dome growth and pyroclastic flows have also occurred.
Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/ Darwin Volcanic Ash Advisory Centre (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AU/messages.html
POAS Costa Rica 10.20°N, 84.233°W; summit elev. 2708 m
OVSICORI-UNA reported that fieldwork at Poás on 16 December showed new geyser activity from a vent on the N flank of the lava dome that formed in 2011. A water-and-mud fountain rose 5-6 m high, flowed into the lake, and built a terrace along the S shore. Gas-and-steam plumes rose from the lava dome.
Geologic Summary. The broad, well-vegetated edifice of Poás, one of the most active volcanoes of Costa Rica, contains three craters along a N-S line. The frequently visited multi-hued summit crater lakes of the basaltic-to-dacitic volcano, which is one of Costa Rica's most prominent natural landmarks, are easily accessible by vehicle from the nearby capital city of San José. A N-S-trending fissure cutting the 2,708-m-high complex stratovolcano extends to the lower northern flank, where it has produced the Congo stratovolcano and several lake-filled maars. The southernmost of the two summit crater lakes, Botos, is cold and clear and last erupted about 7,500 years ago. The more prominent geothermally heated northern lake, Laguna Caliente, is one of the world's most acidic natural lakes, with a pH of near zero. It has been the site of frequent phreatic and phreatomagmatic eruptions since the first historical eruption was reported in 1828. Poás eruptions often include geyser-like
ejection of crater-lake water.
Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) http://www.ovsicori.una.ac.cr/
SORIKMARAPI Sumatra (Indonesia) 0.686°N, 99.539°E; summit elev. 2145 m
CVGHM lowered the Alert Level for Sorikmarapi on 30 December from 2 to 1 (on a scale of 1-4).
Geologic Summary. Sorikmarapi is a forested stratovolcano with a 600-m-wide summit crater containing a crater lake and substantial sulfur deposits. A smaller parasitic crater (Danau Merah) on the upper SE flank also contains a crater lake; these two craters and a series of smaller explosion pits occur along a NW-SE line. Several solfatara fields are located on the eastern flank. Phreatic eruptions have occurred from summit and flank vents during the 19th and 20th centuries.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/
TUNGURAHUA Ecuador 1.467°S, 78.442°W; summit elev. 5023 m
IG reported moderate seismic activity at Tungurahua during 28 December-3 January. On 31 December small steam emissions were observed, and on 3 January a gas-and-steam plume rose 200 m above the crater. Ash-fall from last week's explosions accumulated to a depth of 2-4 mm in villages to the SW.
Geologic Summary. The steep-sided Tungurahua stratovolcano towers more than 3 km above its northern base. It sits ~140 km S of Quito, Ecuador's capital city, and is one of Ecuador's most active volcanoes. Historical eruptions have all originated from the summit crater. They have been accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. The last major eruption took place from 1916 to 1918, although minor activity continued until 1925. The latest eruption began in October 1999 and prompted temporary evacuation of the town of Baños on the N side of the volcano.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG) http://www.igepn.edu.ec/index.php/recursos/noticias.html
Ongoing Activity
FUEGO Guatemala 14.473°N, 90.880°W; summit elev. 3763 m
INSIVUMEH reported that during 29 December-3 January explosions from Fuego generated ash plumes that rose 400-800 m above the crater; the plumes usually drifted SSW and WSW, but on 30 December they drifted 10 km E and NW. During the week explosions generated shock waves and rumbling sounds that were detected 10 km away. House windows and roofs vibrated in nearby villages. Incandescence emanated from the crater at night, and avalanches traveled SW into the Taniluyá and Ceniza drainages, and S in the Santa Teresa drainage during 29 December-2 January. On 3 January the wind lifted ash to an altitude of 500 m. Based on information from satellite observations, the Washington VAAC reported that a possible ash plume drifted SE on 3 January. That same day, information from INSIVUMEH and satellite imagery indicated small emissions that rose to an altitude of 4.9 km (16,000 ft) a.s.l and drifted SE.
Geologic Summary. Volcán Fuego, one of Central America's most active volcanoes, is one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between 3,763-m-high Fuego and its twin volcano to the N, Acatenango. Construction of Meseta volcano continued until the late Pleistocene or early Holocene, after which growth of the modern Fuego volcano continued the southward migration of volcanism that began at Acatenango. Frequent vigorous historical eruptions have been recorded at Fuego since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows. The last major explosive eruption from Fuego took place in 1974, producing spectacular pyroclastic flows visible from Antigua.
Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/geofisica/vulcanologia/boletin%20formato.htm, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html
HIERRO Canary Islands (Spain) 27.73°N, 18.03°W; summit elev. 1500 m
Instituto Geográfic Nacional (IGN) reported that during 28 December-3 January, the submarine eruption continued S of El Hierro Island. The tremor signal almost disappeared for a few hours on 28 December, after three hours with pulses every 30 seconds. The tremor amplitude started increasing again at approximately 16:35. Most of the days, large lava fragments and fine material could be observed on the emission area.
Twenty-four seismic events were located during this period, most of them grouped in the central part of the island, extending offshore both to the N and S. The depth of most of these events ranged between 9 and 23 km, with a maximum magnitude of 2.5. GPS data analyses showed very little deformation, with a slight trend to the N in the stations located at the N of the island.
Geologic Summary. The triangular island of Hierro is the SW-most and least studied of the Canary Islands. The massive Hierro shield volcano is truncated by a large NW-facing escarpment formed as a result of gravitational collapse of El Golfo volcano about 130,000 years ago. The steep-sided 1500-m-high scarp towers above a low lava platform bordering 12-km-wide El Golfo Bay, and three other large submarine landslide deposits occur to the SW and SE. Three prominent rifts oriented NW, NE, and south at 120 degree angles form prominent topographic ridges. The subaerial portion of the volcano consists of flat-lying Quaternary basaltic and trachybasaltic lava flows and tuffs capped by numerous young cinder cones and lava flows. Holocene cones and flows are found both on the outer flanks and in the El Golfo depression. Hierro contains the greatest concentration of young vents in the Canary Islands. Uncertainty surrounds the report of an historical eruption in 1793.
Source: Instituto Geográfico Nacional (IGN) http://www.01.ign.es/ign/layout/volcaVolcanologia.do
KARYMSKY Eastern Kamchatka (Russia) 54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that seismic activity continued at a moderate level at Karymsky during 23-30 December and indicated that possible ash plumes rose to an altitude of 5 km (16,400 ft) a.s.l. Satellite imagery showed a thermal anomaly at the volcano during 22-24 and 27-28 December; clouds prevented views on the other days. The Aviation Color Code remained at Orange.
Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed about 7,600-7,700 radiocarbon years ago. Construction of the Karymsky stratovolcano began about 2,000 years later. The latest eruptive period began about 500 years ago, following a 2,300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been Vulcanian or Vulcanian-Strombolian with moderate explosive activity and occasional lava flows from the summit crater. Most seismicity preceding Karymsky eruptions has originated beneath Akademia Nauk caldera, which is located immediately S of Karymsky volcano and erupted simultaneously with Karymsky in 1996.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/current/kzm/index.html
KILAUEA Hawaii (USA) 19.421°N, 155.287°W; summit elev. 1222 m
During 28 December-3 January, HVO reported that the lava lake circulated and periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater, remaining below the inner ledge (75 m below the crater floor). Almost daily measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and fresh spatter nearby.
Incandescence was visible from small spatter cones on the E and S edges of the Pu'u 'O'o crater floor and along the 21 September 2011 fissure on the SE flank of the Pu'u 'O'o cone. Geologists on an overflight reported that pahoehoe lava flows were significantly broader (700-1,000 m) across the coastal plain and were entering the ocean along a 900 m wide area of the coast on 27 December. Lava flows continued to be active about 6.8 km SE of Pu'u 'O'o and entered the ocean W of Ka'ili'ili on 28 December. During 29 December-2 January a web camera showed no surface activity on the pali, weak sporadic flows near the coast, and weak plumes from the ocean entry. At night during 31 December-2 January incandescence was seen above the pali; on the night of 1 January ground based observers reported lava on the pali. Clouds prevented observations from a web camera on 3 January.
Geologic Summary. Kilauea, one of five coalescing volcanoes that comprise the island of Hawaii, is one of the world's most active volcanoes. Eruptions at Kilauea originate primarily from the summit caldera or along one of the lengthy E and SW rift zones that extend from the caldera to the sea. About 90% of the surface of Kilauea is formed of lava flows less than about 1,100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 sq km, destroying nearly 200 houses and adding new coastline to the island.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO) http://hvo.wr.usgs.gov/
KIZIMEN Eastern Kamchatka (Russia) 55.130°N, 160.32°E; summit elev. 2376 m
KVERT reported moderate seismic activity at Kizimen during 23-30 December and a large thermal anomaly that was detected daily in satellite images. Video and satellite observations indicated that a large lava flow on the E flank continued to effuse. Gas-and-steam plumes drifted 150 km N and 30 km SE on 24 and 27 December, respectively. The Aviation Color Code remained at Orange.
Based on information from Yelizovo Airport (UHPP) and analysis of satellite imagery, the Tokyo VAAC reported that an ash plume rising to an altitude of 5.2 km (17,000 ft) a.s.l. drifted NW on 28 December.
Geologic Summary. Kizimen is an isolated, conical stratovolcano that is morphologically similar to Mount St. Helens prior to its 1980 eruption. The summit of Kizimen consists of overlapping lava domes, and blocky lava flows descend the flanks of the volcano, which is the westernmost of a volcanic chain north of Kronotsky volcano. The 2,376-m-high Kizimen was formed during four eruptive cycles beginning about 12,000 years ago and lasting 2,000-3,500 years. The largest eruptions took place about 10,000 and 8300-8400 years ago, and three periods of longterm lava-dome growth have occurred. The latest eruptive cycle began about 3,000 years ago with a large explosion and was followed by lava-dome growth lasting intermittently about 1,000 years. An explosive eruption about 1,100 years ago produced a lateral blast and created a 1.0 x 0.7 km wide crater breached to the NE, inside which a small lava dome (the fourth at Kizimen) has grown. A single explosive eruption, during 1927-28, ha
s been recorded in historical time.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/current/kzm/index, Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
POPOCATEPETL México 19.023°N, 98.622°W; summit elev. 5426 m
CENAPRED reported that during 28 December-3 January steam-and-gas emissions rose from Popocatépetl and a gas plume rose to an altitude of 1 km on 28 December. Two small landslides were recorded inside the crater on 2January. During 2-3 January gas plumes rose to an altitudes of 600-700 m above the crater and drifted NE.
Geologic Summary. Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5,426 m 70 km SE of Mexico City and is North America's second-highest volcano. Frequent historical eruptions have been recorded since the beginning of the Spanish colonial era. A small eruption on 21 December 1994 ended five decades of quiescence. Since 1996 small lava domes have incrementally been constructed within the summit crater and destroyed by explosive eruptions. Intermittent small-to-moderate gas-and-ash eruptions have continued, occasionally producing ashfall in neighboring towns and villages.
Source: Centro Nacional de Prevencion de Desastres (CENAPRED) http://www.cenapred.unam.mx/cgi-bin/popo/reportes/consulta.cgi
PUYEHUE-CORDON CAULLE Central Chile 40.590°S, 72.117°W; summit elev. 2236 m
Based on seismicity during 28 December-3 January, OVDAS-SERNAGEOMIN reported that the eruption from the Cordón Caulle rift zone, part of the Puyehue-Cordón Caulle volcanic complex, continued at a low level. Small incandescent explosions were observed at night during 28 December-3 January. Plumes observed with a web camera during the week rose 1-5 km above the crater. Satellite images showed ash plumes drifting 20-80 km N, NNE, NE, and SE during 28 December-3 January, dispersing ash to distances of 100-260 km. On 28 December ash fell as far away Argentina, up to 580 km SE. The Alert Level remained at Red.
Geologic Summary. The Puyehue-Cordón Caulle volcanic complex (PCCVC) is a large NW-SE-trending late-Pleistocene to Holocene basaltic-to-rhyolitic transverse volcanic chain SE of Lago Ranco. The 1799-m-high Pleistocene Cordillera Nevada caldera lies at the NW end, separated from Puyehue stratovolcano at the SE end by the Cordón Caulle fissure complex. The Pleistocene Mencheca volcano with Holocene flank cones lies NE of Puyehue. The basaltic-to-rhyolitic Puyehue volcano is the most geochemically diverse of the PCCVC. The flat-topped, 2236-m-high Puyehue volcano was constructed above a 5-km-wide caldera and is capped by a 2.4-km-wide summit caldera of Holocene age. Lava flows and domes of mostly rhyolitic composition are found on the eastern flank of Puyehue. Historical eruptions originally attributed to Puyehue, including major eruptions in 1921-22 and 1960, are now known to be from the Cordón Caulle rift zone. The Cordón Caulle geothermal area, occupying a 6 x 13 km wide volc
ano-tectonic depression, is the largest active geothermal area of the southern Andes volcanic zone.
Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN) http://www.sernageomin.cl/
SAKURA-JIMA Kyushu 31.585°N, 130.657°E; summit elev. 1117 m
Based on information from JMA, the Tokyo VAAC reported that during 28 and 30 December-3 January explosions from Sakura-jima produced plumes that rose to altitudes of 1.5-2.7 km (5,000-9,000 ft) a.s.l. and drifted NE, E, SE, and S.
Geologic Summary. Sakura-jima, one of Japan's most active volcanoes, is a post-caldera cone of the Aira caldera at the northern half of Kagoshima Bay. Eruption of the voluminous Ito pyroclastic flow was associated with the formation of the 17 x 23-km-wide Aira caldera about 22,000 years ago. The construction of Sakura-jima began about 13,000 years ago and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kita-dake summit cone ended about 4,850 years ago, after which eruptions took place at Minami-dake. Frequent historical eruptions, recorded since the 8th century, have deposited ash on Kagoshima, one of Kyushu's largest cities, located across Kagoshima Bay only 8 km from the summit. The largest historical eruption took place during 1471-76.
Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html
SHIVELUCH Central Kamchatka (Russia) 56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that moderate seismic activity was detected at Shiveluch during 23-30 December. Satellite imagery showed a daily thermal anomaly over the lava dome and gas-and-steam plumes drifting 30 km N and SE on 24 and 27 December, respectively. Ground-based observers noted that a viscous lava flow continued to effuse in the crater formed during a 2010 eruption. Moderate fumarolic activity at the lava dome was observed during 22-24 December; clouds prevented observations on the other days of the week. The Aviation Color Code remained at Orange.
Geologic Summary. The high, isolated massif of Shiveluch volcano (also spelled Sheveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group and forms one of Kamchatka's largest and most active volcanoes. The currently active Molodoy Shiveluch lava-dome complex was constructed during the Holocene within a large breached caldera formed by collapse of the massive late-Pleistocene Strary Shiveluch volcano. At least 60 large eruptions of Shiveluch have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Frequent collapses of lava-dome complexes, most recently in 1964, have produced large debris avalanches whose deposits cover much of the floor of the breached caldera. Intermittent explosive eruptions began in the 1990s from a new lava dome that began growing in 1980. The largest historical eruptions from Shiveluch occurred in 1854 and 1964.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/current/kzm/index.html
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